This invention relates to a novel composition which combines in a single product the corrosion-inhibiting characteristics of the guanidinium, phosphonate, alkaline earth cation, and chromate ions having a pH and solubility in aqueous solutions compatible with aluminum and ferrous alloys and organo-polymeric binders.
There are many pigments which will enhance, in varying degrees, the protection of aluminum and ferrous surfaces against the encroachment of corrosive attack in humidified atmospheres, aqueous and saline solutions. These, for instance, include the chromates, molybdates, phosphates, and oxides of zinc, calcium, strontium, barium, cobalt, lead, etc., and are generally rather specific in their action depending on the particular mechanism of inhibition involved; but, for more generalized use, it requires a mixture of pigments to provide a broader spectrum of corrosion protection. This invention is unique in that its components may synergistically reinforce the protective characteristics by broadening the mechanism of inhibition; in addition, the aqueous solubility of the product is adequate for leaching from an organo-polymeric binder, thereby protecting against the encroachment and spread of the corrosive attack as well as for incorporation in aqueous and saline solutions to inhibit the attack on exposed aluminum and ferrous alloy surfaces in an equipment or systems-oriented construction.